Conventionally, a so-called single wafer vapor phase growth apparatus is known as an apparatus for growing a silicon epitaxial layer on a main surface of a silicon single crystal substrate. The single wafer vapor phase growth apparatus has an almost disk-shaped susceptor for supporting the silicon single crystal substrate, and can perform a vapor phase growth of the silicon epitaxial layer by heating the silicon single crystal substrate on the susceptor from both sides as well as by feeding silicon raw materials onto a main surface of the substrate. More specifically, the susceptor has a pocket for positioning the silicon single crystal substrate in a central part of the main surface and is designed to support the silicon single crystal substrate within the pocket.
Incidentally, when the silicon single crystal substrate is nonuniformly heated, slip dislocation easily occurs in the silicon epitaxial layer formed on an upper part of a thermally stressed part of the main surface. Therefore, in order to prevent this slip dislocation from occurring, for example, a susceptor having a pocket of which a bottom surface in the central part is made deeper than that in the outer peripheral part (see, e.g., Japanese Patent Application Publication Unexamined Tokukaisho-61-215289) or a susceptor having a pocket of which a bottom surface is swelled out in a shape of a spherical surface (see, e.g., Japanese Patent Application Publication Unexamined Tokukaisho-62-262417) is used in the vapor phase growth apparatus to uniformly heat the silicon single crystal substrate.
However, even if the susceptors disclosed in the above-described two documents are used, an occurrence frequency of the slip dislocation varies by individual susceptors. Therefore, the improvement is required so that the occurrence of the slip dislocation can be surely reduced irrespective of differences in susceptors.
An object of the present invention is to provide a vapor phase growth apparatus capable of surely reducing the occurrence frequency of the slip dislocation and a vapor phase growth method using the apparatus.